Internal combustion engine systems tend to be quite dynamic. A rotating crankshaft of an engine used to provide torque to a load accelerates and decelerates with the firing of the individual cylinders, for example. The load driven by the engine can also have varying resistance to being rotated or otherwise generate torsional or other forces additive or subtractive to forces provided by the engine. External factors such as vibrations from a vehicle employing the engine system can add further complexity to the dynamic environment.
Loads commonly driven in engine systems may be electrical generators, pumps, propulsion drives, compressors or any of a variety of other devices. In many systems a mechanism commonly referred to as a torsional coupling is positioned operably between an engine and a driven load to transfer torque from the engine. Due to relatively harsh operating conditions such torsional couplings may be relatively robust in design. Despite best efforts, complex vibrations and deflections within the driveline comprised of the engine crankshaft, torsional coupling and parts of a driven unit can eventually cause failure or performance degradation in various of the system components. Commonly owned U.S. Pat. No. 7,775,890 to Shaffer is directed to a flexible drive train having an axial and radial motion limiter. The limiter in Shaffer appears to be configured to limit a maximum axial movement and a maximum radial movement between a flywheel and a driven member, presumably to mitigate wear or fatigue.